LIDAR-Lite altitude or distance sensor

The LIDAR-Lite v3HP is a compact laser distance sensor from Garmin, used as an altimeter that measures height above a surface. It fires a near-infrared laser at the ground or at a target and calculates distance from the time the reflection takes to return, which makes it suited to terrain-relative altitude measurement in landing, hover and low-altitude flight.

The sensor suits small and medium unmanned aircraft and other robotic platforms that need a lightweight height-above-ground reference. It is a laser time-of-flight sensor rather than a barometric device, so it reports the separation to the surface below instead of height relative to a pressure reference, and it works at short range, up to 40 m on a target with 70 percent reflectivity.

The main performance figures are a resolution of 1 cm and a typical accuracy of 5 cm below 2 m and 2.5 cm at 2 m or more, with some nonlinearity present below 1 m. The update rate on a 70 percent reflective target is typically above 1 kHz, although sensitivity is reduced at high update rates. These numbers matter for an integrator because the update rate sets how quickly a flight controller sees a change in height, and the nonlinearity below 1 m affects the final seconds of a landing flare.

On the electrical side, the unit runs from a nominal 5 V supply (4.5 V minimum, 5.5 V maximum) and draws 65 mA when idle and 85 mA during an acquisition. A 680 microfarad electrolytic capacitor is required close to the sensor. Two interfaces are provided: I2C in fast mode at 400 kb/s with a default 7-bit address of 0x62, and a PWM interface with an external trigger input and an output proportional to distance at 10 microseconds per centimeter. A power enable pin lets the host switch the sensor off. The housing measures 40.18 x 54.99 x 35 mm and the weight is 38 g. Operating temperature is -20 to 60 degrees C, and the water rating is IEC 60529 IPX7, which covers incidental immersion up to 1 m for 30 minutes.

The laser operates at a nominal wavelength of 905 nm with 1.3 W peak power and is classified as a Class 1 laser product under EN/IEC 60825-1. Garmin states conformity with the performance standards for laser products under 21 CFR 1040, apart from characteristics covered by a variance.

Typical applications are drone altitude hold and automatic landing, terrain following, robotics and other installations that need a precise short-range height reading.